Meeting Abstract
Seal whiskers (vibrissae) vibrate distinctly when moved through the water. Variations in this vibrational signal may convey information about the flow features in the environment to enable these animals to accomplish their impressive hydrodynamic sensing and tracking behaviors. In order to better understand the signal input to the seal’s sensory system, laser Doppler vibrometry (LDV) and high speed videography were utilized to measure the vibrations of excised harbor seal whiskers from stranding necropsy procedures. Testing was conducted in a research water tunnel across the range of biologically relevant swim speeds for this species (0.5-2.5 m/s) and at two angles of attack (0 and 90 degrees). LDV was used to capture single-point recordings of motion in the cross-stream direction, while high speed video tracking provided multi-point frequency measurements and imaging of whole-whisker motion in the streamwise direction. Across both methods, the measured vibration frequencies were within the known detectable vibrotactile range of the animal. When the two methods are compared, differences in the dominant vibration frequencies were observed. Coarse analysis of vibration modes from high speed video tracking was developed and supplemented with visualization of vibration modes through solid modeling based on geometries from CT scanning. The combination of these methods provides a more comprehensive insight into the seal vibrotactile system.
